Do sows eat more consistently when their feed is mixed with water?

Details

The researchers investigated differences in eating speed between individual pregnant sows and the influence of feeding dry versus wet feed. The experiment included 39 Norwegian Landrace × Yorkshire non-lactating sows: 13 primiparous and 26 multiparous animals.

The same sows received dry and wet feed in two sequential experimental periods. In period 1, each sow was offered 2.2 kg of a standard concentrate feed without added water. In period 2, each received the same weight of concentrate, mixed with water at a feed-to-water ratio of 1:4 by weight. The sows were housed in groups of 4 or 5 in pens with individual feeding stalls. Weighed feed allocations were poured into the troughs before the sows were allowed access. Eating time was limited to 15 minutes on day 1, 10 minutes on day 2, 5 minutes on day 3, 2 minutes 30 seconds on day 4, and 1 minute 15 seconds on day 5. At each designated time, the troughs were covered to block access, and the remaining feed was carefully removed and weighed.

For dry feed, mean consumption rates were 183.2 g/min over the first 5 minutes and 169.7 g/min over the first 10 minutes. For wet feed, the corresponding rates were 1,859.8 g/min and 1,060.7 g/min. After 5 minutes, sows had consumed an average of 41.6% of the dry feed, with a range of 19.5–79.1% and a coefficient of variation (CV) of 31.0%. For wet feed, they had consumed 84.5%, with a range of 54.3–99.1% and a CV of 14.9%.

After 10 minutes, sows had consumed 77.1% of the dry feed, with a range of 33.9–100.0% and a CV of 24.9%; 5 of the 39 sows had eaten their entire allocation. With wet feed, they had consumed 96.4% of the ration after 10 minutes, with a range of 72.7–99.1% and a CV of 6.4%.

Dry-feed eating speed was positively correlated with sow body weight at both 5 minutes (R = 0.72, P < 0.001) and 10 minutes (R = 0.75, P < 0.001). For wet feed, the correlation was weak at 5 minutes (R = 0.36, P < 0.05), and there was no correlation at 10 minutes (R = 0.20, P > 0.10).

The researchers concluded that dry feed resulted in greater individual variation in feed consumption rate than wet feed. Their concluding statement also described consumption rate as correlated with sow liveweight for dry feed but not significantly related to liveweight for wet feed; the detailed results nevertheless reported the weak correlation at 5 minutes for wet feed.